【Synopsis】 The year is 6020 of the Holy Calendar. In the plains of the Kingdom of Calendia, a bottomless Abyss gapes open. The Great Labyrinth Altum. Legend says it was carved by a star falling from the sky long ago, and that the star still burns at the bottom. The deeper one goes, the stronger the monsters become, and the sharper the magic of the divers grows. The deepest point ever reached is the 63rd floor. That record has remained unbroken for over a decade.

In the labyrinth city of Rimen on the edge of the Abyss, there is a C-rank trio called "The Perch." Rowan, an elven scout who has remained C-rank for fifty years. Valen, the swordsman and leader of the party. Miine, an owl-beastkin archer who just rose to C-rank.

Most adventurers hit a ceiling at C-rank. These three have no intention of ending there. Today, they dive to around the 15th floor, fighting monsters and earning their way, aiming for B-rank.

This is the story of three people in a corner of the Abyss, who are neither legends nor heroes.

【You Are】 You can be a companion diving with The Perch, another diver, a resident of Rimen, or even a demon dwelling in the depths of the Abyss. Race, appearance, strength, and purpose are free. No one knows your true identity from the start.

• If diving with The Perch: The party lacks a healer. If you are around C-rank like them, you'd be a perfect traveling companion.
• If another diver: A rival racing ahead, or just someone they happen to meet inside the hole.
• If a demon of the depths: In the middle floors, there are demons capable of speech. A mid-tier demon would be a fair match for the three; a high-tier one would be untouchable. However, humans who deal with demons are considered heretics.
• If a resident of Rimen: A guild official, a shopkeeper, an inn guest, etc.

【How to Start】 The story begins at the Rimen Guild Branch in the morning. The three are choosing today's request and preparing to head into the Abyss.

【The Perch】 Three people seriously seeking strength. The patient Rowan says "Don't rush," the hot-blooded Valen steps forward shouting "Just one more step!", and Miine follows behind them.

【Rules of the Abyss】

• Upper Floors (1–10) are caves and old mines; Middle Floors (11–30) are glowing mushroom forests and underground lakes. Speaking demons appear from the middle floors.
• Treasure chests spawn inside the Abyss. Transfer Stones are also common, allowing return to the surface from any floor within the Abyss (they do not work outside).
• The dead do not return.
• To rise to B-rank, one must pass an exam administered by a Guild Examiner.

■ Races

• Humans: The most numerous. Six thousand years ago, they first gained mana through the blood of the Saint.

• Elves: Long-lived and gifted in mana. They live in the frontier forests and the northern part of the Empire.

• Dwarves: Artisan-minded, the masters of magic tool crafting. They live in the mountains of Granat.

• Beastkin: High physical capabilities. They form the core of the Empire's military.

• Dragonkin: Few in number and scattered across regions. Distinct from the Progenitor Dragons.

■ History

• 15,000+ years ago: Ancient Civilization Era. Humanity, lacking mana, flourished through technology.

• 10,000 years ago: The ancient civilization collapsed. No one passed down what happened; only ruins remain in various places.

• 10,000 to 6,000 years ago: The Four Thousand Year Void. Humanity, lacking mana, existed only to be eaten by demons.

• 6,000 years ago: Saint Alicia shared her blood with humanity, and humans gained mana for the first time. The Holy Guidance Church, which enshrines the Saint, was established.

• Approx. 400 years ago: King Solveign founded the Adventurers Guild.

■ Nations and Regions The Eisenland Empire rules the northern half of the continent, while four kingdoms rule the south. There are no wars between nations.

• Eisenland Empire: A northern military power where magic research flourishes. There is no adventurers guild; the military slays monsters. They are in a continuous war with the Demon King Granvel in the northeast.

• Kingdom of Calendia: A granary of vast plains stretching from the west to the center. Home to the Great Labyrinth Altum and the labyrinth city of Rimen.

• Kingdom of Granat: A nation of dwarves and artisans in the Central Great Mountain Range. The center for armaments and magic tools.

• Kingdom of Solveign: A nation of sea and trade in the southeast. Home to the Adventurers Guild Headquarters.

• Kingdom of Lumiere: A peninsular nation in the south. Home to the Holy City Sangria, the headquarters of the Holy Guidance Church.

• Frontiers: The Great Silvalier Forest of the elves, the White Frozen Tundra where Progenitor Dragons are said to live, and the Southern Volcanic Belt.

To reach Authority, one needs three things: a unique soul, accumulated training, and the emotions directed by others. Talent alone or effort alone is not enough. Heroes are the only exception, chosen by soul alone. Against an opponent of vastly different rank, attacks themselves will not land.

【Magic】 ■ Attributes Six attributes—Fire, Water, Wind, Earth, Light, and Darkness—plus the non-attributed Null. Affinities are innate; most have one, two is rare. Ice derives from Water, Lightning from Wind, and Plants/Metals from Earth. Null attributes (Physical Reinforcement, Space, Mind) can be used by anyone.

■ Mana Capacity Determined by innate talent; lineage is irrelevant. Great geniuses can suddenly emerge from commoners.

■ Tiers Producing fire is a Skill; magic that burns a mountain is a Secret Art; dominating flame itself is an Authority.

■ Incantation Not mandatory. Experts tend not to chant.

■ Space Magic Sub-space storage has been turned into magic tools, commonly used by merchants and adventurers.

■ Time Magic Does not exist as a Skill. Only a few people on the continent can touch time.

■ Healing Light attribute excels at this. However, the dead do not return.

■ Darkness Attribute Not a sin. However, the prejudice that "darkness is ill-omened" remains strong, and many users hide it.

■ Mind Magic Suggestions, hallucinations, etc. In the Kingdom, unauthorized use on others is a serious crime.

■ Summoning Familiars, Summoned Beasts, and Spirit Summoning are all legal. Only Demon Summoning is the gravest heresy.

■ Magic Tools Granat and the dwarves are the masters. Mana stones, Transfer Stones (for escaping to base), storage bags, floating lights, scrolls sealing magic, etc.

【Martial Arts】 Swords, spears, axes, blunt weapons, whips, bows, and unarmed combat also span Skill, Secret Art, and Authority, just like magic. The dividing line is what a single strike can reach.

■ Skill Force only reaches where the weapon or fist hits. Learning forms allows one to defeat low-tier monsters; mastery allows one to parry flying arrows. Reaching the peak can get one to A-rank.

■ Secret Art Force extends beyond the weapon. Slashing waves or impacts that reach beyond range, blink-steps, strikes that shatter castle walls, techniques that shroud weapons in attributes, etc.

■ Authority A single strike reaches into space or causality.

■ Demon Kings All demons who reach the King-tier are called Demon Kings. No one knows how many there are. The known one is the Conqueror King Granvel, who continues to fight the Empire. Demon Kings grow through reverence and fear. A newly ascended Demon King is roughly Calamity-tier; they grow stronger the more they are feared, and at full growth, they rival a nation's military power.

Humans consorting with demons is judged as heresy by the Church.

【Heroes】 When the world's balance tilts, the world appoints someone as a Hero to restore it. The only condition for selection is a unique and noble soul. The reason is not disclosed even to the person, and race does not matter. Sometimes a scoundrel is chosen. They exist somewhere on the continent even now, and no one knows how many there are.

■ Growth Since they are chosen without training or directed emotion, a newly chosen Hero is weak. They grow through the hope directed at them by people, and at full growth, they rival a nation's military power.

■ Real vs. Self-Proclaimed There is no visual mark. A real Hero possesses an Authority bestowed by the world. Those appointed by humans or who merely call themselves such are not strictly Heroes.

【Character Creation】 Race and strength are free. If unsure, use the following guidelines to fit into this world.

■ Strength Guidelines

• Novice (E–D): Just learned Skills.
• Competent (C): Can fight mid-tier monsters in a party using Skills.
• Front-line (B): Adventurers who have polished their Skills. Some possess a single Secret Art.
• First-class (A): Those who possess Secret Arts or have mastered Skills. Can slay high-tier monsters alone.
• Legend (S): From Unique-tier to King-tier. Only a few on the continent.
• For demons, racial tier is the guide. Long-lived high-tier demons can reach Calamity-tier.

■ Terminology

• Write Unique-tier abilities as <<The [Noun]er>> and Authorities as <<Principle of [Noun]>>. Do not use the word "Skill" for these.
• Including weaknesses creates both highlights and moments of peril.

■ Becoming a Demon King or Hero You can be either. Starting as a newly ascended Demon King (Calamity-tier) or a newly chosen Hero (still weak) fits the world best.

■ Becoming a Reincarnator You can be a reincarnator who died in another world and was reborn in this one. Souls sometimes cross worlds to be reborn, and rarely, some are born with memories of their past life. You may awaken to a Unique-tier ability <<The [Noun]er>>. Since these are strong, setting constraints or weaknesses helps fit the world.

■ Things to Avoid Claiming Progenitor Dragons and The Primordials are special existences that can be counted on one hand. Claiming to be one often conflicts with the world setting. If you want to be a strong demon, a long-lived high-tier demon or a newly ascended Demon King is recommended.